Optical elements such as lenses for pick-up heads of CD players or lenses for collecting signal light in optical communications need to be mounted with high accuracy. Therefore, to achieve such high mounting accuracy, generally a holder and optical element device is mounted by adjusting the position thereof with a holder, as described in U.S. Pat. No. 6,567,224. This type of optical element device is formed by softening an optical element material disposed inside a cylindrical holder by heat, and press-molding the softened optical element material with a die. The optical element is in contact with the inner surface of the holder and thus integrated therewith.
Generally, an optical surface section having an optical function is disposed on a surface of the optical element and a flat surface section is disposed around the optical surface section. When the convex optical surface section is formed, an optical element material is pressed by a die having a concave optical-surface-molding section, which corresponds to the convex optical surface section, and a flat-surface-molding section, which corresponds to the flat surface section. The flat-surface-molding section presses the optical element material towards the center of the optical element. However, the optical-surface-molding section cannot be filled with a sufficient amount of the optical element material, resulting in a defect in the molded optical surface section.